I noticed the new securityProbe 5E has a jumper in the back, what is this used for?

AKCP AdministratorsecurityProbe Series, Support

That jumper is a 120 ohm switch, as in some cases of Modbus integration 120 ohms is needed on the RS485 input, so that has been added.

AKCP AdministratorI noticed the new securityProbe 5E has a jumper in the back, what is this used for?